Sun, 27 Jul 2008 07:58:58 BST CiteULike: dchen's Sharma http://www.citeulike.org/user/dchen/author/Sharma CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2910642 <i>Soft Matter, 2008, 4, 1151 - 1157, DOI: 10.1039/b714376a</i><br /><br />Stimuli-responsive polymer gels have received considerable attention due to their singular mechanical properties, which make them materials of choice for niche applications. Polymer gels comprising either physical or chemical cross-links can undergo controlled and reversible shape changes in response to an applied field. The stimulus or external field applied may include thermal, electrical, magnetic, pH, UV/visible light, ionic or metallic interactions or combinations thereof. The shape change can manifest itself in two-dimensional actuation, bending motion, or three-dimensional actuation, volume change. This reversible contraction and expansion of polymer gels as well as their mechanical properties are similar to that of biological muscles. This review will describe and critique some of the recent advances in the field of stimuli-responsive polymer gels including the design of new classes of polymeric gels, controlled actuation in response to external stimuli, and ability to tailor material properties for different applications. Stimuli-responsive polymer gels Suk-Kyun Ahn Rajeswari Kasi Seong-Cheol Kim Nitin Sharma Yuxiang Zhou Soft Matter, 2008, 4, 1151 - 1157, DOI: 10.1039/b714376a 2008-06-20T14:55:03-00:00 Soft Matter, 2008, 4, 1151 - 1157, DOI: 10.1039/b714376a 2008 gel polymer review http://www.citeulike.org/user/dchen/article/2753670 <i>Physical Review Letters, Vol. 98, No. 24. (2007)</i><br /><br />The static dielectric properties of liquid and solid water are investigated within linear response theory in the context of ab initio molecular dynamics. Using maximally localized Wannier functions to treat the macroscopic polarization we formulate a first-principles, parameter-free, generalization of Kirkwood's phenomenological theory. Our calculated static permittivity is in good agreement with experiment. Two effects of the hydrogen bonds, i.e., a significant increase of the average local moment and a local alignment of the molecular dipoles, contribute in almost equal measure to the unusually large dielectric constant of water. Dipolar Correlations and the Dielectric Permittivity of Water Manu Sharma Raffaele Resta Roberto Car doi:10.1103/PhysRevLett.98.247401 Physical Review Letters, Vol. 98, No. 24. (2007) 2008-05-04T15:35:50-00:00 2007 Physical Review Letters 98 24 APS 2007 charge correlation focus water